Alfentanil

CLINICAL USE

Opioid analgesic:

Short surgical procedures

Intensive care sedation

DOSE IN NORMAL RENAL FUNCTION

IV injection:

Spontaneous respiration: up to

—
500 micrograms over 30 seconds;
supplemental dose: 250 micrograms
assisted ventilation: 30–50

—
micrograms/kg; supplemental dose:
15 micrograms/kg

By IV infusion with assisted ventilation:

loading dose 50–100 micrograms/kg as
bolus or fast infusion over 10 minutes,
followed by 0.5–1 micrograms/kg/minute.
Discontinue infusion 30 minutes before
anticipated end of surgery

For analgesia and suppression of

respiratory activity during intensive care
with assisted ventilation: by IV infusion
2 mg/hour, adjusted according to response
(usual range 0.5–10 mg/hour)

For more rapid initial control give 5 mg

IV in divided portions over 10 minutes
(slower if hypotension or bradycardia
develops); additional doses of 0.5–1 mg
may be given by IV injection during short
painful procedures

PHARMACOKINETICS

Molecular weight &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp :
453 (as hydrochloride)

%Protein binding &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp :
92

%Excreted unchanged in urine &nbsp &nbsp :
0.4

Volume of distribution (L/kg) &nbsp &nbsp &nbsp :
0.4–1

half-life – normal/ESRD (hrs)&nbsp &nbsp &nbsp :
1–2 (average
90 minutes)/
Unchanged

DOSE IN RENAL IMPAIRMENT

GFR (mL/MIN)

20 to 50 &nbsp &nbsp : Dose as in normal renal function

10 to 20 &nbsp &nbsp : Dose as in normal renal function

<10 &nbsp &nbsp &nbsp &nbsp &nbsp :
Dose as in normal renal function

DOSE IN PATIENTS UNDERGOING RENAL REPLACEMENT THERAPIES

CAPD &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp:
Not dialysed. Dose as in normal renal function

HD &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp :
Not dialysed. Dose as in normal renal function

HDF/high flux &nbsp :
Unknown dialysability. Dose as in
normal renal function

CAV/VVHD &nbsp &nbsp &nbsp:
Not dialysed. Dose as in normal renal function

IMPORTANT DRUG INTERACTIONS

Potentially hazardous interactions with other drugs

Antidepressants: possible CNS excitation

or depression (hypertension or
hypotension) in patients also receiving
MAOIs (including moclobemide) – avoid
concomitant use; possibly increased
sedative effects with tricyclics

Antifungals: metabolism inhibited by

fluconazole and ketoconazole (risk
of prolonged or delayed respiratory
depression); metabolism possibly inhibited
by itraconazole

Antivirals: concentration possibly

increased by ritonavir

Sodium oxybate: enhanced effect of

sodium oxybate – avoid concomitant use

ADMINISTRATION

Reconstition

–

Route

IV bolus,

IV infusion

Rate of Administration

See dose

Comments

Alfentanil can be mixed with sodium

chloride 0.9%, glucose 5%, or compound
sodium lactate injection (Hartmann’s
solution) at a concentration of 0.5 mg/
mL, but can be used at 2 mg/mL or even
undiluted at 5 mg/mL.

OTHER INFORMATION

Free fraction of drug is increased in renal

failure, hence dose requirements may be
reduced

IV administration: 500 micrograms

alfentanil has peak effect in 90 seconds,
and provides analgesia for 5–10 minutes
(in unpremedicated adults)

Transient fall in BP and bradycardia may

occur on administration

Analgesic potency = ¼ that of fentanyl

Duration of action = ⅓ that of an equi-

analgesic dose of fentanyl

Onset of action = 4 times more rapid than

an equi-analgesic dose of fentanyl

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